Using SatPointer to Set Up Offset Multi-Feed Dishes
A multi-feed satellite dish receives signals from two or more orbital positions with separate LNBs mounted on one reflector. The central LNB usually points at the primary satellite, while additional feeds are placed to either side for nearby satellites. Correct positioning depends on more than simply copying an azimuth and elevation from a satellite finder.
SatPointer provides the geographical and orbital reference needed for this work. By entering the installation location and selecting the required satellites, you can compare their azimuth, elevation, and polarization direction before adjusting the feed rail. This makes it easier to distinguish the angular separation between satellites from the physical offset built into an offset reflector.
That distinction matters. A satellite may be several degrees away in the sky, but the LNB does not move by exactly the same number of degrees along a bracket. The dish geometry, focal length, rail design, reflector shape, and local mounting method all influence the final position.
Establish The Main Dish Reference
Begin by choosing the satellite that will serve as the primary focus of the dish. This is normally the position requiring the strongest signal, the largest number of desired services, or the most demanding beam coverage. The central LNB should be aligned with this satellite before any secondary feed is installed.
Enter the exact installation location in SatPointer rather than relying on a nearby city. A difference of several kilometres rarely creates a major pointing error, but accurate coordinates provide a dependable azimuth, elevation, and polarization reference. Check that the selected satellite matches the intended orbital position, since similarly named services can operate from different longitudes.
The primary direction is the foundation for every additional calculation. If the central LNB is not correctly aligned, a secondary feed may appear to compensate for the error while both satellites remain weak or unstable.
Separate Sky Separation From Reflector Offset
In a multi-feed installation, “offset angle” can describe two different measurements. The first is the apparent angular distance between two satellites as seen from the receiving site. The second is the reflector’s built-in offset angle, which describes how the dish surface directs a signal when the dish appears to point below the satellite.
SatPointer is most useful for determining the first measurement. Compare the azimuth and elevation values for the primary and secondary satellites. The differences show whether the second satellite is higher, lower, farther east, or farther west in the local sky. For nearby orbital positions, these differences provide a practical starting point for locating the second LNB.
The reflector offset itself normally comes from the dish manufacturer or a measurement of the antenna. It should not be added blindly to the satellite elevation shown by SatPointer. The software describes the required line of sight, while the dish bracket may use a physical elevation scale that has already been adjusted for the reflector design.
Calculate The Secondary Feed Position
Run SatPointer separately for the primary and secondary satellites at the same site. Record the azimuth and elevation for both positions, then calculate the signed differences:
- Azimuth difference = secondary azimuth minus primary azimuth
- Elevation difference = secondary elevation minus primary elevation
- Polarization difference = secondary skew minus primary skew
The signs are important. A satellite with a lower azimuth may require the additional LNB to sit on the western or eastern side of the rail, depending on the dish orientation and whether the feed assembly is viewed from the front or behind the reflector. Avoid assuming that “east” always means “right” without checking the antenna’s physical viewpoint.
For satellites close together, the azimuth and elevation differences can often guide the initial feed placement. For larger separations, the relationship becomes three-dimensional. A simple horizontal rail may not place the LNB at the exact focal position, so the feed may need vertical adjustment as well as sideways movement.
| Measurement | What SatPointer Provides | How It Helps In A Multi-Feed Setup |
|---|---|---|
| Azimuth | Horizontal direction from the site to the satellite | Identifies the east-west component of feed separation |
| Elevation | Upward angle of the satellite line of sight | Indicates whether the secondary feed should sit higher or lower |
| Polarization skew | Rotation required for the LNB probe | Helps match signal polarization and reduce cross-polar interference |
| Orbital separation | Difference between satellite positions | Establishes the initial spacing relationship between feeds |
| Dish size and beam data | Estimated reception requirements and coverage information | Helps assess whether one reflector can separate both signals effectively |
Translate Angular Difference Into Feed Movement
The sky angle is not always equal to the distance measured along the feed bracket. A rough linear estimate can be made with the focal length: lateral movement is approximately the focal length multiplied by the angular difference in radians. For example, a small angular separation across a longer focal-length reflector creates a larger physical displacement than the same separation on a compact dish.
This estimate is only a starting point. Offset dishes often use curved or stepped feed rails, and the focal point can shift as the LNB moves away from the central axis. Some multi-feed holders allow only sideways movement, while others provide height, tilt, and rotation adjustments. The farther the secondary satellite is from the main focus, the more valuable those adjustments become.
Place the central LNB at the calculated focal point first. Then install the secondary LNB on the predicted side of the holder, leaving enough movement for fine tuning. Tighten the fasteners only enough to prevent the feed from falling; final alignment requires small controlled adjustments.
Match Skew And Check Polarization
Each satellite has its own polarization orientation at the receiving location. Even when two satellites are close in azimuth and elevation, their LNB skew settings may differ slightly. Rotate each LNB according to its own SatPointer reference rather than keeping all feeds parallel.
The correct rotation can be judged from the rear of the dish or from the front, but the direction reverses depending on the viewpoint. Mark the top of each LNB and make small rotational changes while monitoring signal quality. A useful skew matching guide can help clarify the relationship between polarization, LNB rotation, and the observer’s position.
Signal strength alone is not enough for this stage. Look for quality, bit-error performance, or receiver lock stability. Incorrect skew can allow a strong transponder to appear usable while increasing interference from the opposite polarization.
Verify The Alignment With Real Transponders
After the initial placement, test known active transponders from both the primary and secondary satellites. Use at least one horizontal and one vertical service where possible. This reveals whether the problem is caused by pointing, skew, cable loss, an unsuitable LNB, or incorrect receiver settings.
If the primary satellite is strong but the secondary one is weak, move the secondary LNB in very small increments. Adjust sideways first, then height, tilt, and rotation separately. Changing several settings at once makes it difficult to identify which movement improved the result.
If both satellites are weak, return to the central alignment. A multi-feed holder can conceal a basic dish-pointing error because the reflector may be aimed between the intended orbital positions. Recheck the main satellite in SatPointer, confirm the selected location, and make sure the dish mast is vertical. A tilted mast distorts elevation and azimuth adjustments.
Use Practical Tools For Repeatable Results
Record the SatPointer values, initial feed positions, receiver readings, and final corrections. These notes are useful when replacing an LNB, relocating the dish, or adding another satellite later. A photograph showing the rail orientation and LNB rotation marks can also prevent confusion during maintenance.
For installers who publish setup instructions or support several sites, a customizable widget generator can make direction data easier to share. A site owner can also place an embedded SatPointer tool on a technical blog or forum so readers can calculate local satellite directions without leaving the page.
- Use precise installation coordinates and verify the selected orbital position.
- Align the primary satellite before positioning any secondary LNB.
- Treat azimuth and elevation differences as sky angles, not guaranteed bracket distances.
- Set each LNB’s polarization skew independently.
- Confirm both satellites with real transponders and signal-quality readings.
Make The Final Alignment
SatPointer gives a reliable directional reference, but the final multi-feed result comes from combining that data with the reflector’s focal geometry and careful receiver testing. Start with the calculated relationship, preserve the direction signs, and make adjustments gradually rather than forcing the feed into a guessed position.
Use the calculated values to mark the bracket, tune each satellite at its strongest quality reading, and secure the assembly only after checking all intended services. With accurate site data and disciplined fine adjustment, an offset dish can provide stable reception from multiple orbital positions using one reflector.